[1.5.0] Deprecate some functions (#2582)

* Add deprecated macro to zstd.h, mark certain functions as deprecated

* Remove ZSTD_compress.c dependencies on deprecated functions

contrib/VS2005/zstdlib/zstdlib.vcproj

@@ -473,10 +473,6 @@
 				RelativePath="..\..\..\lib\common\xxhash.h"
 				>
 			</File>
-			<File
-				RelativePath="..\..\..\lib\common\zbuff.h"
-				>
-			</File>
 			<File
 				RelativePath="..\..\..\lib\zdict.h"
 				>